event/ServerSocket: migrate from class Error to C++ exceptions

src/net/Resolver.cxx

@@ -19,8 +19,7 @@
 
 #include "config.h"
 #include "Resolver.hxx"
-#include "util/Error.hxx"
-#include "util/Domain.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <string>
 
@@ -35,12 +34,9 @@
 #include <string.h>
 #include <stdio.h>
 
-const Domain resolver_domain("resolver");
-
 struct addrinfo *
 resolve_host_port(const char *host_port, unsigned default_port,
-		  int flags, int socktype,
-		  Error &error)
+		  int flags, int socktype)
 {
 	std::string p(host_port);
 	const char *host = p.c_str(), *port = nullptr;
@@ -87,12 +83,9 @@ resolve_host_port(const char *host_port, unsigned default_port,
 
 	struct addrinfo *ai;
 	int ret = getaddrinfo(host, port, &hints, &ai);
-	if (ret != 0) {
-		error.Format(resolver_domain, ret,
-			     "Failed to look up '%s': %s",
-			     host_port, gai_strerror(ret));
-		return nullptr;
-	}
+	if (ret != 0)
+		throw FormatRuntimeError("Failed to look up '%s': %s",
+					 host_port, gai_strerror(ret));
 
 	return ai;
 }

src/net/Resolver.hxx

@@ -24,24 +24,21 @@
 #include "Compiler.h"
 
 struct addrinfo;
-class Error;
-class Domain;
-
-extern const Domain resolver_domain;
 
 /**
  * Resolve a specification in the form "host", "host:port",
  * "[host]:port".  This is a convenience wrapper for getaddrinfo().
  *
+ * Throws #std::runtime_error on error.
+ *
  * @param default_port a default port number that will be used if none
  * is given in the string (if applicable); pass 0 to go without a
  * default
  * @return an #addrinfo linked list that must be freed with
- * freeaddrinfo(), or NULL on error
+ * freeaddrinfo()
  */
 addrinfo *
 resolve_host_port(const char *host_port, unsigned default_port,
-		  int flags, int socktype,
-		  Error &error);
+		  int flags, int socktype);
 
 #endif

src/net/SocketError.hxx

@@ -21,6 +21,7 @@
 #define MPD_SOCKET_ERROR_HXX
 
 #include "Compiler.h"
+#include "system/Error.hxx"
 #include "util/Error.hxx" // IWYU pragma: export
 
 #ifdef WIN32
@@ -136,4 +137,22 @@ NewSocketError()
 	return NewSocketError(GetSocketError());
 }
 
+gcc_const
+static inline std::system_error
+MakeSocketError(socket_error_t code, const char *msg)
+{
+#ifdef WIN32
+	return MakeLastError(code, msg);
+#else
+	return MakeErrno(code, msg);
+#endif
+}
+
+gcc_pure
+static inline std::system_error
+MakeSocketError(const char *msg)
+{
+	return MakeSocketError(GetSocketError(), msg);
+}
+
 #endif

src/net/SocketUtil.cxx

@@ -26,41 +26,35 @@
 int
 socket_bind_listen(int domain, int type, int protocol,
 		   SocketAddress address,
-		   int backlog,
-		   Error &error)
+		   int backlog)
 {
 	int fd, ret;
 	const int reuse = 1;
 
 	fd = socket_cloexec_nonblock(domain, type, protocol);
-	if (fd < 0) {
-		SetSocketError(error);
-		error.AddPrefix("Failed to create socket: ");
-		return -1;
-	}
+	if (fd < 0)
+		throw MakeSocketError("Failed to create socket");
 
 	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 			 (const char *) &reuse, sizeof(reuse));
 	if (ret < 0) {
-		SetSocketError(error);
-		error.AddPrefix("setsockopt() failed: ");
+		auto error = GetSocketError();
 		close_socket(fd);
-		return -1;
+		throw MakeSocketError(error, "setsockopt() failed");
 	}
 
 	ret = bind(fd, address.GetAddress(), address.GetSize());
 	if (ret < 0) {
-		SetSocketError(error);
+		auto error = GetSocketError();
 		close_socket(fd);
-		return -1;
+		throw MakeSocketError(error, "Failed to bind socket");
 	}
 
 	ret = listen(fd, backlog);
 	if (ret < 0) {
-		SetSocketError(error);
-		error.AddPrefix("listen() failed: ");
+		auto error = GetSocketError();
 		close_socket(fd);
-		return -1;
+		throw MakeSocketError(error, "Failed to listen on socket");
 	}
 
 #if defined(HAVE_STRUCT_UCRED) && defined(SO_PASSCRED)

src/net/SocketUtil.hxx

@@ -27,12 +27,13 @@
 #define MPD_SOCKET_UTIL_HXX
 
 class SocketAddress;
-class Error;
 
 /**
  * Creates a socket listening on the specified address.  This is a
  * shortcut for socket(), bind() and listen().
  *
+ * Throws #std::system_error on error.
+ *
  * @param domain the socket domain, e.g. PF_INET6
  * @param type the socket type, e.g. SOCK_STREAM
  * @param protocol the protocol, usually 0 to let the kernel choose
@@ -40,13 +41,12 @@ class Error;
  * @param backlog the backlog parameter for the listen() system call
  * @param error location to store the error occurring, or NULL to
  * ignore errors
- * @return the socket file descriptor or -1 on error
+ * @return the socket file descriptor
  */
 int
 socket_bind_listen(int domain, int type, int protocol,
 		   SocketAddress address,
-		   int backlog,
-		   Error &error);
+		   int backlog);
 
 int
 socket_keepalive(int fd);